The present invention relates to a load adjustment device having a control element (11) which acts on a setting member (16) which determines the power output of an internal combustion engine, the control element being connected to a driver (4) which is coupled to an accelerator pedal (1) and can, in addition, be moved by means of an electric setting drive (9). The load adjustment device has a desired-value detection element (7) associated with the driver, an actual-value detection element (12) which cooperates with said desired-value detection element (7) and acts on the electric setting drive, the electric setting drive being adapted to be controlled as a function of the values detected by an electronic control device (22).
Load adjustment devices of this kind are provided in motor vehicles for actuation of the throttle valve or the injection pump by means of the accelerator pedal in order, by means of the electronic control device, to intervene in such a manner that, for instance, wheel slippage upon starting as a result of excessive power is avoided. By way of example, if the accelerator pedal is depressed too rapidly, the control device provides that the throttle valve is opened less than corresponds to the position of the accelerator pedal so that the internal combustion engine produces only a reduced power level which avoids a spinning of the wheels. Other automatic interventions in the load adjustment device are necessary if a transmission is to be switched automatically, or if the idling speed is to be set to a constant value even upon different power requirements upon idling. It is also known in the case of such an adjustment device to act by a speed-limiting controller which, by the possibility of uncoupling the control element from the accelerator pedal, provides that in each case that power is set which is necessary in order to maintain the speed set. In addition, it may be desirable, in particular from the standpoint of driving comfort, to provide a progressive or degressive coupling of the accelerator pedal, with the possibility of a reduced or increased power setting as compared with the position of the accelerator pedal.
However, safety factors make it necessary to provide assurance, even in the case of a defect in the control device that, upon backward movement of the position of the accelerator pedal, the power adjustment decreases in synchronism with the position of the accelerator pedal. This has been achieved up to now by safety devices in the electronic control device. Possibilities of defects in the control device are reduced in the manner that the electronic system is constructed with redundance. Nevertheless, too high a power setting which does not correspond to the position of the accelerator pedal is not completely excluded in the event of a defect.
Load adjustment devices of the above mentioned type are, in general, developed in several parts, i.e. certain elements are associated with the accelerator pedal while other elements cooperate with the control element. Such a separate arrangement of the parts means, on the one hand, an increase in the structural size of the load adjustment device while, on the other hand, no assurance is had by the arranging of the structural parts at different points of the vehicle that the parts will cooperate free of reaction with the throttle valve or the injection pump.